Background

In Mexico, those arrested are, in practice, considered guilty until proven innocent -- with predictable results. The great majority of the accused never see a judge or even an arrest warrant.

At present, a person who commits a crime in Mexico has less than a 2 percent chance of being caught and punished, in part because police often ask a person who reports a crime to pay for the case to be solved; a person who refuses risks becoming a suspect him or herself, which discourages cooperation with police. A study released in 2008 indicated that Mexican citizens had extremely low confidence in police action and efficiency, which causes them to shy away from reporting crimes.

With violent crime, particularly crime related to drugs, rampant in Mexico, police are under pressure to make arrests. Rather than being evaluated on the accuracy of arrests, however, officers and even prosecutors are judged solely on the number of incarcerations, meaning that there's little incentive for them to spend time seeking out a crime's actual perpetrator. It is estimated that in nine out of 10 cases, an arrest is made without any scientific evidence -- such as fingerprints or DNA -- whatsoever; Mexico has no comprehensive fingerprint database, and police have little access to forensic equipment. In more than six out of 10 cases, suspects are arrested within three hours of the crime, suggesting that little to no serious detective work could have taken place.

Furthermore, an arrest is often made without the victim having identified the accused. Instead, an initial police investigation identifies the person believed to have committed the act. (This measure is meant to protect the victim, particularly in the case of rape or kidnapping, or when the victim is a minor.) Even when witnesses are called to give testimony, more weight is placed on the paperwork filed before the trial than on live statements.

However, the law does allow a procedure called a careo (short for careo probatorio), in which a defendant may confront his or her accuser face-to-face. The meeting, which must be requested by the suspect, takes places at the penal courts in the jail where the suspect is being held, in the presence of a penal judge, a public defender and the prosecuting and defense attorneys. The suspect, who remains behind bars, may question the victim, with the goal of clarifying any contradictory or confusing testimony and coming to a unanimous truth. The presiding judge may ask questions and may also encourage witnesses to rethink or correct their testimonies.

Often, however, actual practices differ from what's laid out in the law. According to the current constitution, for example, a suspect may be held for a maximum of 48 hours without being charged with a crime, but a 2002 study found that officials adhere to that rule less than half the time. Once a person has been charged, a judge has 72 hours to decide whether a suspect should be tried or released; this limit, too, has been found to be surpassed in more than half of cases.

These abuses, combined with the lack of a proper bail system, mean that many suspects are held without having been given a proper trial: According to a study by the New York-based nonprofit Open Society Institute, as many as 42 percent of Mexico's inmates, or about 90,000 people, have been held without trial.

In June 2008, Mexico passed a monumental amendment to its 1917 constitution that will transform its judicial system from one widely considered arcane and unjust to a system more in line with 21st-century global standards.

In contrast to the "common law" system in place in the United States and elsewhere, in which court decisions are based on legal precedents or prior rulings, Mexico's current system is a "civil law" arrangement, in which each case is decided individually according to the letter of the law.

After the reform officially goes into effect in 2016, trials will be conducted very differently. Currently prosecutors do not present oral arguments, as U.S. lawyers do, but present their cases in writing, via paperwork. A trial has no jury, and often the judge doesn't meet the defendant face-to-face -- one survey showed that 71 percent of defendants never saw a judge before being sentenced. Judges make their decisions in accordance with a strict code of justice that leaves very little room for interpretation, and all evidence is sealed from the public. After the reform, cases will be presented in court with oral arguments, creating greater transparency.

Prosecutors' and judges' roles will also change in 2016. Currently, public prosecutors in Mexico are responsible for researching and building cases, and judges often take part in the gathering of evidence and development of a case. The reform will help separate the act of investigating a case from the process of making a final judgment on that case.

The judicial reform grew out of President Felipe Calderón's efforts to crack down on organized crime, one of the major challenges of his term. Since he took office in December 2006, more than 13,500 people have died as a result of violence involving drug cartels. Calderón has been applauded for deploying 45,000 army troops to fight the gangs, but analysts argue that without significant reform to police and court systems, the measures will stall. Without better investigative practices and cooperation from the public, they say, chances of breaking up the drug cartels are slim.

Among the initial bill's proposals was a measure that would have allowed police and security forces to conduct raids and home searches without permits, but that proposal was removed by Mexico's lower house of Congress, the Chamber of Deputies, before the bill was passed.

One controversial measure, known as arraigo, did survive, however. Arraigo allows police to detain suspects of organized crime -- meaning any crime involving more than three people -- for up to 80 days. Many critics claim that the measure undermines due process and are afraid that it will be abused.